Homemade sandblasters .

[minh-thanh]

I watch a lot of videos about homemade sandblasters on youtube
I have a question :
Has anyone here ever built a sandblaster and used it on your model engine ?

 

[kadora]

I have built very simple sand blaster gun /top sand container/ but i use 0.2 mm
glass powder instead of sand.
Glass powder is perfect for aluminium it stays shiny after blasting.
Plus is good to have 10bar compressor with big airtank /sand blasting needs lot of air.

 

[timo_gross]

I have built very simple sand blaster gun /top sand container/ but i use 0.2 mm
glass powder instead of sand.
Glass powder is perfect for aluminium it stays shiny after blasting.
Plus is good to have 10bar compressor with big airtank /sand blasting needs lot of air.

Do you need 10 bar for the sand blaster? The compressor in the workshop switches off at 4.5 bar, because it needs less power that way. The compressor is quite big, it can run a die-grinder non stop at 4 bar.
How about an air dryer?
minh-thanh is in Vietnam. A lot of moisture in the air, so it will end up in the compressed air line.

Greetings Timo

 

[retailer]

I have one of the sand blasters that has a small container of sand that feeds by gravity into the gun, can use sand (dry), soda or grit - I have my air regulator set for 90PSI - it is a total loss system in that the sand simply blows away into the surrounding area, the idea is that you use it out in the open. It works to a point but makes a bit of a mess, I made the mistake of using it in a confined space approx 3.5m x 3.5m and the sand got into my clothes and hair - every where I went I left a trail of sand until I took a shower and changed my clothes, if you have the room in your workshop I would go for a sandblasting cabinet if not them make sure you have at least 20 or so meters of clear space all around you. If using soda don't be fooled by the small soft powder it will damage you skin, I wasn't sure if any soda was being blown out so I tried it on the palm of my hand - ouch! I learnt my lesson the hard way.

 

[minh-thanh]

Thanks for the comments !

I have one of the sand blasters that has a small container of sand that feeds by gravity into the gun, can use sand (dry), soda or grit - I have my air regulator set for 90PSI - it is a total loss system in that the sand simply blows away into the surrounding area, the idea is that you use it out in the open. It works to a point but makes a bit of a mess, I made the mistake of using it in a confined space approx 3.5m x 3.5m and the sand got into my clothes and hair - every where I went I left a trail of sand until I took a shower and changed my clothes, if you have the room in your workshop I would go for a sandblasting cabinet if not them make sure you have at least 20 or so meters of clear space all around you. If using soda don't be fooled by the small soft powder it will damage you skin, I wasn't sure if any soda was being blown out so I tried it on the palm of my hand - ouch! I learnt my lesson the hard way.

I borrowed and tried a similar one from a friend, it has the same condition as you said. I like the one with the container - Sand Blast Cabinet
I have phoned a few suppliers, but the price is too high for my needs, , and I think it is not too difficult to make one similar but small and fit my needs

 

[dnalot]

I made a standup cabinet sand blaster out of plywood. I lined the inside with a rubber sheet intended as a pond liner. It works great and I have been using it for years.

Mark T

 

[minh-thanh]

I made a standup cabinet sand blaster out of plywood. I lined the inside with a rubber sheet intended as a pond liner. It works great and I have been using it for years.

Mark T

A great way to save money
Can you post some pictures ?

 

[dnalot]

Here you go Minh Thanh.

The vacuum is used to rid the cabinet of dust so you can see what you are doing. It is a special vacuum for cleaning out a fireplace. It handles very fine dust very well. For lighting in side I used CFL bulbs protected by mason jars. The window is removable so I can tape a protective plastic shield that needs to be replaced often. Made from .5" plywood covered inside back and side walls with innertube type rubber sheet. 35 PSI of air works best. I have a 5HP compressor and it keeps up easily.

Mark T

 

[SmithDoor]

I watch a lot of videos about homemade sandblasters on youtube
I have a question :
Has anyone here ever built a sandblaster and used it on your model engine ?

I purchased a sandblasted from Harbor Freight and a bag of play sand at Home Depot and blasted outside. Simple and fast

Dave

 

[minh-thanh]

dnalot !
Thanks for your pictures !
I watched a lot of homemade sandblasting videos, but never seen anything similar to yours. As for wood and lining , it's an easy material to get at a very low cost - it's probably free if I ask some of my friends

SmithDoor !
I choose the type with container because: small area and dust
" fast , simple , economical " : that is my goal , but it depends on a few things that i have to think carefully ( difficulties ...., there's no need to talk about it on the forum and I don't like to talk about it )

 

[Ozwes007]

Just a heads up, you should never use sand for sandblasting. It will give you silicosis. banned in most countries and places of work.

 

[Peter Twissell]

Just a heads up, you should never use sand for sandblasting. It will give you silicosis. banned in most countries and places of work.

What is the world coming to?
Can't use sand for sandblasting.
Can't use solder for soldering.
Can't use paint stripper for paint stripping....

Back to the subject, I built a blasting cabinet from cheap hardboard.
It is roughly a 2 foot cube, but the bottom is an inverted pyramid with an exit hole for recovering used abrasive.
It is suspended from the roof of my shop and can be pulled up into the roof space and out of the way when not in use.

 

[Mike Ginn]

Firstly, you must not use sand as it can result in silicosis.

I use 5micron ground glass which is cheap and I blast all my models. It gives a uniform finish which I then spray with clear acrylic.

The size is approx. 62x54x28 and there are many suppliers of this model costing around £130. It would be simple to make this out of plywood and use a piece of polyXX as the window. Gloves are available on eBay. You must have a vacuum extraction system which has a vortex separator between the blaster and the vacuum cleaner. I would suggest purchasing the blasting gun if you are making a plywood home built unit. My purchased blaster has a very basic media/air mixer in the base which doesn’t really work and requires far too much air. I have a 8bar 50ltr twin compressor which struggles and can overheat. The correct solution is to use a mixing valve as shown in many youtube videos. These can be assembled from gas fittings. The required air pressure and volume should then drop.
Hope this is of help
Mike

 

[timo_gross]

Firstly, you must not use sand as it can result in silicosis.

I use 5micron ground glass which is cheap and I blast all my models. It gives a uniform finish which I then spray with clear acrylic.

Hallo Mike,

at least the comments are of help for me.
I do not want to argue that dust is problematic.
The message is clear.

• Do pay attention what you use for blasting.
• Try to inhale as less as possible of it.
• Try to inhale as less as possible or the dust that you are removing from the parts.
• Do not put your cat (or other living creatures) into the sandblasting cabinet.
  I guess he will like the "new clean cat toilet" (something I have to keep in mind )

But.... isn*t glas basically the same as sand? I mean it is both mainly Silicon-Dioxide. I am not sure why glas dust would be any better/different than sand dust, unless the glas beads do not break up into fine dust.
Same goes for grinding diy cut glas with a flap disc. (not healthy at all)

It seems the most difficult parts are the nozzle, gloves and sand mixer. The box you showed is rel. cheap.
Is the dust extraction necessary in your opinion or is it a nice to have? I mean is it necessary to be able to see what you are doing, or can I just take my time to let dust settle before I open the box? ( but I blow blast air into the box that needs to go somewhere? Some sort of exhaust is needed I guess )

My neighbor was inquiring a unit from a local company, but he did not go in for it because it was in the thousands of USD and not high enough on his list.
So using his is not the short term solution I was hoping for. (still hoping he finds a used unit )

Greetings Timo

 

[timo_gross]

Is one of those vibration tumblers with the small ceramics pyramides providing any overlap? My goal is getting rid of small burrs and machining marks, parts are small and not many at a time.

Greetings Timo

 

[davidyat]

Beware of pessimists, they find problems in every solution!

 

[minh-thanh]

Hi All !
Thanks for the comments !
With dust : sand or glass...it's always not good for health, so let's put that aside. I will take note of this .
My next question is : besides the dust problem , are there other issues to be concerned about ? For example: before and after sandblasting, protect the parts that do not need sandblasting....

 

[ShopShoe]

I can chime in with some clarification:

I have and have used the "end of the air hose" or "bottle blaster" on small parts.

I have a larger pressure blaster that I used in car restoration, but I rarely use it any more. It was worth the expense, but still a time-intensive method that can be used improperly to wreck parts if you're not careful.

I would like to have a blast cabinet and have considered building one. A firm offered a kit of parts for a blast cabinet, along with plans, but I have not checked to see if it is still available.

I made a tumbler, like a rock tumbler, from a quart paint can and a roller base which did not work well. I also made a vibrating cleaner from a Harbor Freight electric oscillating sander and a PVC-Pipe chamber to clean small parts using safety solvent.

Each one of the above approaches had some positives and some negatives. Just like all tool purchases, you have to choose a path and follow it for awhile to see if it is really for you.

--

Regarding abrasives: just like sandpaper. Large, Hard, Sharp grains clean fast, last longer, and give rough appearance. Finishing uses fine materials and takes longer and may also require more work be done ahead with other methods. Abrasive suppliers stock from "Sand" through glass beads, plastic media, and things like walnut shells. If I'm not mistaken, the Statue of Liberty was cleaned with "baking soda" to remove the outer dirt without taking off the patina: they did not want to end up a shiny copper like "brand new." All of these things have some risk to the operator and to the object being treated and you have to plan accordingly when choosing your approach.

If you are using air, you will need a lot of it and it must be dry and clean: More to spend money on. You need a large compressor that can run continuously.

Some type of enclosure or cabinet will allow you to capture and reuse your blasting media, but abrasive wears out and will have to be augmented or replaced. $$$.

Blasting will scratch up your cabinet glass, your face shield and goggles, and everything else. You will need to replace these items frequently.

You don't necessarily need the cabinet vacuum, but you'll decide you do soon. A blast cabinet vacuum is not the same thing as a shop vac and is priced accordingly. Those also wear out: Last time I looked at getting one, the vendor was recommending that you purchase a spare motor assembly at the beginning.

Any blast gun will wear out nozzles quickly and you need lots of spares. All of the parts exposed to the abrasive stream also wear out.

Even in relatively dry conditions, Oxidation will start immediately after blasting. You have to be prepared to handle this immediately as well.

--

If you want to try blasting, I would suggest a small bench-top cabinet or build your own. Have an adequate compressor. Purchase extra viewing lenses and nozzles. Get some different types of abrasives to try and start with non-critical items.

Let us know how it goes, with pictures if you can.

--ShopShoe

 

[stanstocker]

Hallo Mike,

<snip>
But.... isn*t glas basically the same as sand? I mean it is both mainly Silicon-Dioxide. I am not sure why glas dust would be any better/different than sand dust, unless the glas beads do not break up into fine dust.
Same goes for grinding diy cut glas with a flap disc. (not healthy at all)
<snip>

Greetings Timo

Oh Timo...

There you again, letting reality interfere with a good story I had the same thought, you got there first!

Cheers,
Stan

 

[Mike Ginn]

Great comments guys!
Following up on the main points;-
Sand must not be used as the silica causes scaring of the lungs as per the OSHA guidance/regulations. Glass is considered safe as stated by OSHA "....glass dust is classified as amorphous silica dioxide. This type of silica poses no health risks..." As with all dust it is best not to inhale it!

Vacuum extraction is essential. Without it you just can't see what you are doing! We modellers usually have small parts and they often need to be held in some form of jig and it is necessary to blast all around the part. Being able to see what you are doing using an internal light is essential. I have a domestic Henry vacuum cleaner and a Commando Dust Cyclonic separator which catches 99% of the air bourn dust particles. The Henry bag never fills. I did need to make adaptors etc. A replaceable plastic film on the main window is a good idea.

I have a tumbler but it is always sitting on the shelf. Takes far too long to work. However if your issue is de-burring then, with the suitable media, its a great solution. Media is dependent on the object material. Walnut shells? Usually requires experimentation to find the right media

To protect parts I have 2 approaches. On the outside of a flywheel I use painters blue tape. I over tape then cut back with a sharp knife (scalpel). For holes like cylinder bores, I make a disk usually from acrylic and clamp with a bolt. I also use PTFE rod to block holes. Its is reasonable soft, easy to machine but expensive but I have a lot of it! To protect the blasted surface I use clear acrylic spray using a (cheap) small Humbrol all purpose airgbrush. The earlier picture I posted of the Wyvern valve push rod and timing contacts are about 1 year old from blasting and painting.

If you are building your own take a look at the YouTube videos for Harbor Freight Blast Cabinets for the mods especially for the mixer valve.

Finally I would echo the comment from ShopShoe regarding the amount of air needed. Remember it needs a continuous supply when operating. I reduced the size of the jet (remade it) in the gun to limit the flow. I have yet to modify my very basic mixer which continues to cause problems. You always seem to need more air than available!

I attach a name plate to show the following. Plate machined with a 0.3mm V cutter leaving many cut lines. The total cut depth was 0.5mm on 1.5mm brass sheet. Name plate then "sand" Blasted and immediately acrylic sprayed. The top surface was then rubbed down with wet/dry 600/1000 grit paper. All the machining marks were "lost" The right hand image shows more detail. Blasted about 6 months ago.

Good conversation!

Mike

ps I am still trying to work out how to get my cat into the cabinet but I have used Cat Litter in my Tumbler - its a good media!!